Dataset Information

Identification and characterization of the cognate anti-sigma factor and specific promoter elements of a T. tengcongensis ECF sigma factor.

ABSTRACT: Extracytoplasmic function (ECF) σ factors, the largest group of alternative σ factors, play important roles in response to environmental stresses. Tt-RpoE1 is annotated as an ECF σ factor in Thermoanaerobacter tengcongensis. In this study, we revealed that the Tt-tolB gene located downstream of the Tt-rpoE1 gene encoded the cognate anti-σ factor, which could inhibit the transcription activity of Tt-RpoE1 by direct interaction with Tt-RpoE1 via its N-terminal domain. By in vitro transcription assay, the auto-regulation ability of Tt-RpoE1 was determined, and band shift assay showed that Tt-RpoE1 preferred to bind a fork-junction promoter DNA. With truncation or base-specific scanning mutations, the contribution of the nucleotides in -35 and -10 regions to interaction between Tt-RpoE1 and promoter DNA was explored. The promoter recognition pattern of Tt-RpoE1 was determined as 5' tGTTACN(16)CGTC 3', which was further confirmed by in vitro transcription assays. This result showed that the Tt-RpoE1-recognized promoter possessed a distinct -10 motif (-13CGTC-10) as the recognition determinant, which is distinguished from the -10 element recognized by σ(70). Site-directed mutagenesis in Region 2.4 of Tt-RpoE1 indicated that the "D" residue of DXXR motif was responsible for recognizing the -12G nucleotide. Our results suggested that distinct -10 motif may be an efficient and general strategy used by ECF σ factors in adaptive response regulation of the related genes.

SUBMITTER: Liu J

PROVIDER: S-EPMC3397946 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:BackgroundThe expression of genes in Corynebacterium glutamicum, a Gram-positive non-pathogenic bacterium used mainly for the industrial production of amino acids, is regulated by seven different sigma factors of RNA polymerase, including the stress-responsive ECF-sigma factor SigH. The sigH gene is located in a gene cluster together with the rshA gene, putatively encoding an anti-sigma factor. The aim of this study was to analyze the transcriptional regulation of the sigH and rshA gene cluster and the effects of RshA on the SigH regulon, in order to refine the model describing the role of SigH and RshA during stress response.ResultsTranscription analyses revealed that the sigH gene and rshA gene are cotranscribed from four sigH housekeeping promoters in C. glutamicum. In addition, a SigH-controlled rshA promoter was found to only drive the transcription of the rshA gene. To test the role of the putative anti-sigma factor gene rshA under normal growth conditions, a C. glutamicum rshA deletion strain was constructed and used for genome-wide transcription profiling with DNA microarrays. In total, 83 genes organized in 61 putative transcriptional units, including those previously detected using sigH mutant strains, exhibited increased transcript levels in the rshA deletion mutant compared to its parental strain. The genes encoding proteins related to disulphide stress response, heat stress proteins, components of the SOS-response to DNA damage and proteasome components were the most markedly upregulated gene groups. Altogether six SigH-dependent promoters upstream of the identified genes were determined by primer extension and a refined consensus promoter consisting of 45 original promoter sequences was constructed.ConclusionsThe rshA gene codes for an anti-sigma factor controlling the function of the stress-responsive sigma factor SigH in C. glutamicum. Transcription of rshA from a SigH-dependent promoter may serve to quickly shutdown the SigH-dependent stress response after the cells have overcome the stress condition. Here we propose a model of the regulation of oxidative and heat stress response including redox homeostasis by SigH, RshA and the thioredoxin system.

Dataset Information

Identification and characterization of the cognate anti-sigma factor and specific promoter elements of a T. tengcongensis ECF sigma factor.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets